1. Technical Field
The present invention relates to machine tools and more particularly to a vise stop configured to assure repeatability in the placement of a work piece in relationship to the machine tool.
2. Background of the Invention
Oftentimes in machining operations, it is necessary to perform repetitious machine tool functions on a plurality of substantially identical parts for mass producing a particular piece or part. Numerically or computer controlled milling machine tools, including mills and lathes, are highly adapted to this type of function. Nevertheless, each new work piece must be set up with particular care to assure that reference surfaces are positioned substantially identically, that is, positioned in the same X, Y and Z axes so as to assure repeatability of the machining operation and quality of the final product.
In most machining environments today, a Y axis may be fixed by setting the jaws of a machine tool vise in a specific location and then setting the vice so that the fixed jaw becomes a reference point on the Y axis. Similarly, the seat of the vice, once the vice is installed and bolted to the table of the machine tool, establishes a repeatable reference for the Z axis. Location then of the work piece on the Y axis and repeatability of this location has remained challenging.
A number of solutions have been proposed with limitations. In some instances, devices lack rigidity and may loose their ability to produce accurate positioning of piece after piece in relationship to the cutting tool. This is particularly the case where the device or stop is multi-jointed and includes excessive joints and degrees of movement or rotation. Other problems may arise where the vise stop effectively limits access of the machine tool or the cutting tool to various surfaces of the work piece. In some instances, the configuration of the vise stop limits the ability of the cutting tool to access only the top surface of the work piece.
What is needed is a simple and effective vise stop which allows repeatability of placement of parts, particularly along the X axis, in relationship to the cutting tool and which allows the work piece to be machined on all surfaces and faces which would otherwise be exposed to the cutting tool. Additionally, the device for locating the work piece should also include the ability to position the stop in relationship to both the vice and the work piece so that it may be moved out of the way when necessary or kept in position as required.
The present invention is directed to a vise stop for positioning a workpiece in a vise, the vise stop including a crossbar having a first end, a second end and a mounting surface. The crossbar is configured for attachment to the vise and a first stop arm is pivotally connected to the crossbar first end for positioning a workpiece along an X axis. In the preferred embodiment of the invention, a second stop arm is pivotally connected to the crossbar second end.
In the preferred embodiment of the invention, a friction disc is compressively disposed between an inner face of both the first and second stop arms and the first and second ends of the crossbar. The friction disc allows the stop arm to be frictionally positionable and rotatable about its point of attachment to the crossbar end. The friction disc may be configured as a fiber washer, a spring washer or a compressible o-ring. This feature of the invention allows an operator the freedom of angularly positioning and repositioning the first and second stop arms as required without loosening the carriage bolt or other means for attaching the first and second stop arms to the crossbar.
In the preferred embodiment of the invention, the stop arms each include an adjustable stop tip. A first adjustable stop tip threadedly engages a distal end of the first stop arm, the first adjustable stop tip extending from the distal end of the first stop arm at an angle lying substantially perpendicular to a longitudinal axis of the first stop arm. Similarly, a second stop tip threadedly engages a distal end of the second stop arm, the second adjustable stop tip extending from the distal end of the second stop arm at an angle lying substantially perpendicular to a longitudinal axis of the first stop arm. Both the first and second adjustable stop tips may be locked in position by a locknut.
Other advantages will become apparent to those skilled in the art from the following detailed description read in conjunction with the appended claims attached hereto.